The Degradation And Slow-release Formulation Of Pyoluteorin

Pyoluteorin (Plt) is a biological pesticide in weeding and inhibiting the growth of bacteria and fungi, especially Oomycetes. However, the instability of its chemical structure easily leads to degradation of Plt during storage and field application, which greatly limits its utilities. So it's essential to study the mechanism of Plt degradation, or find an effective way to prolonging its biological effects. To address this purpose, the following research was designed in two parts.First, study the degradation mechanism. Plt samples with high purity (99.3%) were purified from M18 (rsmA-) bacterial strain. And then, degradated the Plt sample in pure water under ultraviolet light. Analyze the degraded products by HPLC, LC/MS, and NMR, we hypothesize possible degradation products, and base on these products we hypothesize a possible mechanisms and pathways of Plt degradation.Sencond, look for new applications. According to researches in clinical drug discovery and pesticide improvement, the"slow-release formulation of Plt-SiO2"(nanophase material of silicon dioxide loading Plt drugs) was synthesized by HOM and EISA methods. Several conditions (including drug loading, surfactant, solvent, etc) were optimized, and the final experimental formula was m(Plt:Brij56:TMOS:HC(laq))=0.04:1.4 : 2:1, synthesizing by HOM method. This formula can continuously release 85.13(±2.03)%of Plt in 28 days. The structure of the formula was further characterized using small-angle diffraction (XRD), TEM imaging, and N2 adsorption-desorption isotherms.This is the first report to study the Plt degradation pathways by analyzing the degraded products from purified Plt in several precise methods. And also this is the first report to study the synthesis of slow-release Plt formulations using nanophase materials. It is important to the further study on storage and field application of Plt.